The invention relates to a bone screw and a method for locking a bone screw into a bore. The bore can be provided in e.g. an implant, a plate, a nail or the like.
Angular stable locking of implants, plates, nails or the like is associated with positive impact on fracture healing. US 2004/0158252 A1 discloses an implant for osteosynthesis, such as, for example, a bone nail, with an implant body which has at least one bore with a threaded portion and a bone screw which engages the thread when it is threaded into a bone for the fixation of the implant body. The threaded bore has an annular groove the diameter of which is larger than the thread outer diameter, and which receives a ring of a deformable material with an inner diameter, which is larger than the outer diameter of the thread of the bone screw so that the ring extends partially into the bore.
Various designs to increase the fragment stability are commercially available. These solutions are based on modification of the locking holes (e.g. an internal thread) and/or complex technical solutions including altered operative techniques with additional implant components.
However, the mentioned concepts suffer from their respective technical complexity, the required costly implant, plate or nail modification by e.g. additional threads, and a missing backward compatibility to existing implants, plates, nails or the like.